


Day Four

by FellQueen (Nikasha)



Series: Kinktober 2019 [4]
Category: Undertale (Video Game)
Genre: Bad Dirty Talk, Come Marking, Dirty Talk, Face-Fucking, Facials, M/M, Underfell Sans (Undertale), kustard - Freeform
Language: English
Status: Completed
Published: 2019-10-05
Updated: 2019-10-05
Packaged: 2020-11-24 03:27:21
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 748
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20900891
Author URL: https://archiveofourown.org/users/Nikasha/pseuds/FellQueen
Summary: Day FourPrompt: Dirty talkPairing: Kustard (Underfell Sans/Classic Sans)





	Day Four

**Author's Note:**

> Changed out the prompt for a different one. Also, didn’t realize I like using Red in pairings this much until now. The things you learn.
> 
> Anyway, have fun

Red tilted his head, gaze locked on where his cock disappeared into Sans’s mouth. He ran a hand across the gently moving skull, a bubbling purr in his throat.  
Sans glanced up briefly at him, his eyelights hazy and unfocused, then returned to what he was doing.  
“Fuck, babe,” Red sighed happily, jerking his hips just to hear Sans choke and flinch. “Your mouth is better than a cunt.”  
The blue that had faded somewhat from Sans’s face flared up again as he closed his eyes and sucked hard, earning a loud groan from Red.  
“Yesss, suck me dry,” he rambled, hooking his fingers around Sans’s throat to feel the magic pulse as he swallowed. “You’re pretty on your knees.”  
Sans wiggled a bit, his hips twitching at the air before he stopped with a soft noise of frustration that made Red hiss.  
“Aww, the little whore feeling needy?” He watched Sans’s eyelights flicker, grinning. “You’re so easy. Don’t worry your pretty little head, I’ll take care of you after we’re done.”  
Sans grunted again and shifted his weight to bring a hand up to Red’s length, running his thumb along the underside in a way that had Red clutching at the armchair.  
“Damn it,” he growled. “Your fucking hands...Hey, little bitch. Want me to fuck your mouth?” He was grinning again at Sans’s involuntary glance upwards. “Yeah you do. Want me to use you like the little waste of space you are.” He abruptly stood, Sans yelping around his cock as he tried to fall back, but Red kept his grip on his partner’s head. He clicked his tongue. “Where you goin’, precious? I just told you, I need your mouth.”  
He started thrusting into Sans’s face, groaning. He reeled himself in to get a good look at his toy, taking in the twitching phalanges and watering sockets. He could hear Sans sucking in small breaths through his nasal cavity before a particularly unruly push had him gagging again, hand grabbing Red’s femur. He was fighting Red’s hold, but not hard, just an instinctive urge to free himself from the obstruction.  
Red could see the blue glow from Sans’s shorts.  
“You’re so hot like this,” he laughed shakily. “Being used like you wanna be. Getting off on it. Such a good slut.”  
Sans moaned and Red echoed him.  
“There’s no real way to shut you up except putting a cock in your face.” He grinned as Sans’s fluster turned to a mildly embarrassed glare. “Don’t look at me like that, I can see your pussy from here. It’s like a fucking lightbulb. I bet you’re messy as hell down there, too, clenching on nothing and wishing you could have something inside you.”  
Sans closed his eyes again like Red’s words were caresses against him and sucked hard. Red exhaled in a short burst.  
“Gonna cum,” he rasped, panting through jagged teeth. “Gonna cum all over your slutty face. ‘S all you’re good for, being painted in my jizz.”  
Sans whined.  
“Yeah? You want me to mark you, babe?” It was getting hard to breathe, but he refused to look away from the skeleton at his feet. “Fuck—“ He jerked Sans away. As his partner sucked in a gasping mouthful of air, Red came, painting crimson across Sans’s teeth and face. He closed one eyesocket, trying to keep it out of his skull. “Stars, you...you gorgeous piece of shit.” He laughed shakily, running a thumb through the red on Sans’s cheek and smearing it.  
Sans was still coughing and gasping, but he managed to wheeze, “Damn it, man...we talked about this.”  
Red scoffed. “Talked about how much you love this shit? Yeah we talked about it.”  
Sans gave an unhappy groan, but the blue flush was still present under Red’s spunk.  
Red dropped to his knees to give him a kiss, but pulled away again quickly to give him a thorough once-over. “Mine.”  
Sans winced and looked away. “Yeah,” he said softly.  
Red smeared more of the magic into his bone. “I wish they could all see you like this,” he murmured, voice dark. “Covered in my magic, exhausted by me. I wish they could see what kind of needy trash you really are.”  
Sans shuddered.  
Red leaned in to lick a stripe up Sans’s cheek. “Shh, baby. I’m here.” Sans’s low moan was beautiful music as Red brushed his fingers against the wet fabric between his partner’s legs. “Let me take care of you.”

**Author's Note:**

> Link used:  
https://twitter.com/idek_uggy/status/1178349575725174786?s=21
> 
> Day five is oviposition!


End file.
